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Publication numberUS20090213028 A1
Publication typeApplication
Application numberUS 12/394,033
Publication dateAug 27, 2009
Filing dateFeb 26, 2009
Priority dateFeb 27, 2008
Also published asUS8344552, US8710701, US20130293024
Publication number12394033, 394033, US 2009/0213028 A1, US 2009/213028 A1, US 20090213028 A1, US 20090213028A1, US 2009213028 A1, US 2009213028A1, US-A1-20090213028, US-A1-2009213028, US2009/0213028A1, US2009/213028A1, US20090213028 A1, US20090213028A1, US2009213028 A1, US2009213028A1
InventorsNigel P. Cook, Lukas Sieber, Hanspeter Widmer
Original AssigneeNigel Power, Llc
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Antennas and Their Coupling Characteristics for Wireless Power Transfer via Magnetic Coupling
US 20090213028 A1
Abstract
Optimizing a wireless power system by separately optimizing received power and efficiency. Either one or both of received power and/ or efficiency can be optimized in a way that maintains the values to maximize transferred power.
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Claims(18)
1. A method of forming a wireless power system, comprising:
first optimizing efficiency of power transfer between a transmitter of power to a receiver of wireless power; and
separate from said optimizing efficiency, second optimizing maximum received power in said receiver.
2. A method as in claim 1, wherein said first optimizing and said second optimizing are done according to rules which specify information about both desired efficiency and desired total received power.
3. A method as in claim 2, wherein said rules specify a minimum efficiency for power transfer.
4. A method as in claim 2, wherein said rules specify a minimum received power amount.
5. A method as in claim 1, wherein said optimizing comprises optimizing multiple different aspects simultaneously, including a first aspect that relates to comparing resonance in a source with a resonance in the receiver, and a second aspect that relates to a strength of a coupling between said transmitter and said receiver.
6. A method as in claim 5, wherein said optimizing is carried out separately for a weaker coupling as compared with a stronger coupling.
7. A method as in claim 5, wherein said optimizing comprises maintaining resonance conditions of both said transmitter and said receiver.
8. A method as in claim 5, wherein said optimizing further comprises maintaining a resistance of an inductor in the receiver substantially equal to a series resistance.
9. A method as in claim 5, wherein said optimizing further comprises maintaining a source resistance at a transmitter as less than a series resistance of the transmitter.
10. A system, comprising:
a receiver of a wireless power, including and inductor, a capacitor, and a connection to a load, wherein said receiver has values that are optimized, according to both of power transmitter between a remote transmitter of power that wirelessly transmits the power to the receiver, and also according to a maximum receive power efficiency, that optimizes the maximum received power in the receiver.
11. A system as in claim 10, wherein said receiver has first optimizing and said second optimizing which are done according to rules which specify information about both desired efficiency and desired total received power.
12. A method as in claim 11, wherein said rules specify a minimum efficiency for power transfer.
13. A method as in claim 11, wherein said rules specify a minimum received power amount.
14. A method as in claim 11, wherein said rules optimize multiple different aspects simultaneously, including a first aspect that relates to comparing resonance in a source with a resonance in the receiver, and a second aspect that relates to a strength of a coupling between said transmitter and said receiver.
15. A method as in claim 14, wherein said optimizing is carried out separately for a weaker coupling as compared with a stronger coupling.
16. A method as in claim 14, wherein said optimizing comprises maintaining resonance conditions of both said transmitter and said receiver.
17. A method as in claim 14, wherein said optimizing further comprises maintaining a resistance of an inductor in the receiver substantially equal to a series resistance.
18. A method as in claim 14, wherein said optimizing further comprises maintaining a source resistance at a transmitter as less than a series resistance of the transmitter.
Description
  • [0001]
    This application claims priority from provisional application No. 61/032,061, filed Feb. 27, 2008, the disclosure of which is herewith incorporated by reference.
  • BACKGROUND
  • [0002]
    Our previous applications and provisional applications, including, but not limited to, U.S. patent application Ser. No. 12/018,069, filed Jan. 22, 2008, entitled “Wireless Apparatus and Methods”, the disclosure of which is herewith incorporated by reference, describe wireless transfer of power.
  • [0003]
    The transmit and receiving antennas are preferably resonant antennas, which are substantially resonant, e.g., within 10% of resonance, 15% of resonance, or 20% of resonance. The antenna is preferably of a small size to allow it to fit into a mobile, handheld device where the available space for the antenna may be limited.
  • [0004]
    An embodiment describes a high efficiency antenna for the specific characteristics and environment for the power being transmitted and received.
  • [0005]
    Antenna theory suggests that a highly efficient but small antenna will typically have a narrow band of frequencies over which it will be efficient. The special antenna described herein may be particularly useful for this kind of power transfer.
  • [0006]
    One embodiment uses an efficient power transfer between two antennas by storing energy in the near field of the transmitting antenna, rather than sending the energy into free space in the form of a travelling electromagnetic wave. This embodiment increases the quality factor (Q) of the antennas. This can reduce radiation resistance (Rr) and loss resistance (Rl)
  • SUMMARY
  • [0007]
    The present application describes the way in which the “antennas” or coils interact with one another to couple wirelessly the power therebetween.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • [0008]
    In the Drawings:
  • [0009]
    FIG. 1 shows a diagram of a wireless power circuit;
  • [0010]
    FIG. 2 shows an equivalent circuit;
  • [0011]
    FIG. 3 shows a diagram of inductive coupling;
  • [0012]
    FIG. 4 shows a plot of the inductive coupling; and
  • [0013]
    FIG. 5 shows geometry of an inductive coil.
  • DETAILED DESCRIPTION
  • [0014]
    FIG. 1 is a block diagram of an inductively coupled energy transmission system between a source 100, and a load 150. The source includes a power supply 102 with internal impedance Zs 104, a series resistance R4 106, a capacitance C1 108 and inductance L1 110. The LC constant of capacitor 108 and inductor 110 causes oscillation at a specified frequency.
  • [0015]
    The secondary 150 also includes an inductance L2 152 and capacitance C2 154, preferably matched to the capacitance and inductance of the primary. A series resistance R2 156. Output power is produced across terminals 160 and applied to a load ZL 165 to power that load. In this way, the power from the source 102 is coupled to the load 165 through a wireless connection shown as 120. The wireless communication is set by the mutual inductance M.
  • [0016]
    FIG. 2 shows an equivalent circuit to the transmission system of FIG. 1. The power generator 200 has internal impedance Zs 205, and a series resistance R1 210. Capacitor C1 215 and inductor L1 210 form the LC constant. A current I1 215 flows through the LC combination, which can be visualized as an equivalent source shown as 220, with a value U1.
  • [0017]
    This source induces into a corresponding equivalent power source 230 in the receiver, to create an induced power U2. The source 230 is in series with inductance L2 240, capacitance C2 242, resistance R2 244, and eventually to the load 165.
  • [0018]
    Considering these values, the equations for mutual inductance are as follows:
  • [0000]

    U2=jωMI1
  • [0000]

    U1=jωMI2
  • [0000]
    where:
  • [0000]

    zM=jωM
  • [0000]
    z 1 = z s + R 1 + j ( ω L 1 - 1 ω C 1 ) z 2 = z L + R 2 + j ( ω L 21 - 1 ω C 2 )
    z s =R s +jX s
  • [0000]

    z L =R L +jX L
  • [0000]
    The Mesh equations are:
  • [0000]
    U s + U 1 - z 1 I 1 = 0 I 1 = ( U s + U 1 ) / z 1 U 2 - z 2 I 2 = 0 I 2 = U 2 / z 2 I 1 = U s + z M I 2 z 1 I 2 = z M I 1 z 2 I 2 = z M ( U s + z M I 2 ) z 1 z 2 = z M U s z 1 z 2 - z M 2 I 1 = z M z M I 2 = z 2 U s z 1 z 2 - z M 2
  • [0019]
    where:
      • Source power:
  • [0000]

    P 1=Re{U s I 1*}=UsRe{I 1*} for avg{U s}=0
      • Power into load:
  • [0000]

    P 2 =I 2 I 2*Re{z L }=|I 2|2Re{z L }=|I 2|2 R L
      • Transfer efficiency:
  • [0000]
    η = P 2 P 1 = I 2 I 2 R L U s Re { I 1 } I 2 I 2 = z M z M U s 2 ( z 1 z 2 - z M 2 ) ( z 1 z 2 - z M 2 ) Re { I 1 } = Re { z 2 U s z 1 z - z M 2 }
  • [0023]
    Overall transfer Efficiency is therefore:
  • [0000]
    η = P 2 P 1 = U s 2 R L z M z M ( z 1 z 2 - z M 2 ) ( z 1 z 2 - z M 2 )
  • [0000]

    Def.: z 1 =z 1 z 2 −z M si 2
  • [0000]
    η = P 2 P 1 = R L z M z M z z Re { z 2 z z z } = R L z M z M Re { z 2 z } = R L z M z M Re { z 2 ( z 1 z 2 - z M 2 ) } = R L z M 2 Re { z 1 z 2 2 - z 2 z M 2 } η = P 2 P 1 = R L z M 2 z 2 2 Re { z 1 } - z M 2 Re { z 2 } Re { z 1 } = R s + R 1 Re { z 2 } = R L + R 2 z 2 2 = ( R L + R 2 ) 2 + ( ω L 2 - 1 ω C 2 + X L ) 2 z M 2 = ω 2 M 2 z M 2 = ( j ω M ) 2 = - ω 2 M 2
  • [0000]
    A Transfer efficiency equation can therefore be expressed as:
  • [0000]
    η = P 2 P 1 = ω 2 M 2 R L ( R s + R n ) [ ( R L + R 2 ) 2 + ( ω L 2 - 1 ω C 2 + X L ) ] + ω 2 M 2 ( R L + R 2 )
  • [0000]
    Which reduces in special cases as follows:
    A) when ω=ω0=1/√{square root over (L2C2)}, XL=0 or where
  • [0000]
    ω L 2 - 1 ω C 2 + X L ( ω ) = 0 η = P 2 P 1 = ω 0 2 M 2 [ ( R s + R n ) ( R L + R 2 ) + ω 0 2 M 2 ] R L ( R L + R 2 )
  • [0000]
    B) when ω=ω0, Rs=0:
  • [0000]
    η = P 2 P 1 = ω 0 2 M 2 R L R 1 ( R L + R 2 ) 2 + ω 0 2 M 2 ( R L + R 2 )
  • [0000]
    C) when ω=ω0, Rs=0 RL=R2:
  • [0000]
    η = P 2 P 1 = ω 0 2 M 2 4 R 1 R 2 + 2 ω 0 2 M 2
  • [0000]
    D) when ω=ω0, Rs=0 RL=R2 2R1R2>>ω0 2M2:
  • [0000]
    η = P 2 P 1 ω 0 2 M 2 4 R 1 R 2 ( weak coupling )
  • [0000]
    where:
    Mutual inductance:
  • [0000]

    M=k√{square root over (L 1 L 2)} where k is the coupling factor
  • [0000]
    Loaded Q factors:
  • [0000]
    Q 1 , L = ω L 1 R s + R 1 Q 2 , L = ω L 2 R L + R 2
  • [0000]
    Therefore, the transfer efficiency in terms of these new definitions:
    A) when ω=ω0
  • [0000]
    η = P 2 P 1 = k 2 ω 0 L ω 0 L 2 ( R s + R 1 ) ( R L + R 2 ) 1 + k 2 ω 0 L ω 0 L 2 ( R s + R 1 ) ( R L + R 2 ) R L R L + R 2 η = k 2 Q 1 , L Q 2 , L 1 + k 2 Q 1 , L Q 2 , L R L R L + R 2
  • [0000]
    C) when ω=ω0, RL=R2,(Rs=0):
  • [0000]
  • D) ω=ω0, RL=R2, (Rs=0), 2RnR2>>ω0 2M2
  • [0024]

    1>>k2Q1,ULQ2,UL/2
  • [0000]
    η = P 2 P n k 2 Q 1 , UL Q 2 , UL 4 ( weak coupling )
  • [0000]
    QUL: Q unloaded
  • [0000]
    Q 1 , UL = ω L 1 R 1 ; Q 2 , UL = ω L 2 R 2
  • [0000]
    This shows that the output power is a function of input voltage squared
  • [0000]
    P 2 = f ( U s 2 ) + I 2 I 2 * R L ; I 2 = z M U s z 1 z 2 - z M 2 P 2 = z M z M * R L ( z 1 z 2 - z M 2 ) ( z 1 * z 2 * - z M 2 * ) U s 2 P 2 = z M 2 R L U s 2 z 1 z 2 z 1 * z 2 * + z M + z M 2 ( z 1 z 2 + z 1 * z 2 * ) P 2 = z M 2 R L U s 2 z 1 z 2 2 + z M 2 2 Re { z 1 z 2 } + z M 4 z M = M z M * = - M z M = ω M = z M z M * z M * = - ω 2 M 2 = - z M 2 z M 2 * = - ω 2 M 2 = z M 2 = - z M 2 z M 2 z M 2 * = z M 4 z 1 z 2 = z 1 z 2 z 1 z 2 + z 1 * z 2 * = 2 Re { z 1 z 2 } z 1 z 2 2 = z 1 2 z 2 2
  • Definitions:
  • [0025]

    z 1 R′ 1 +jX 1 ; z 2 =R′ 2 +jX 2
  • [0000]

    |z 1 z 2|2=(R′ 1 2 +X 1 2)(R′ 2 2 +X 2 2)=R′ 1 2 R′ 2 2 +X 1 2 R′ 2 2 +X 2 2 R′ 1 2 +X 1 2 X 2 2
  • [0000]

    Re{z 1 z 2}=Re(R′ 1 +jX 1)(R′ 2 +jX 2)=R′ 1 R′ 2 +X 1 X 2
  • [0000]

    |z M |=X M
  • [0000]
    P 2 = X M 2 R 1 U s 2 R 1 ′2 R 2 ′2 + R 1 ′2 X 2 2 + R 1 ′2 X 1 2 + X 1 2 X 2 2 + 2 X M 2 R 1 R 2 + 2 X M 2 X 1 X 2 + X M 4 P 2 = X M 2 R L U s 2 ( R 1 R 2 + X M 2 ) 2 + R 1 ′2 X 2 2 + R 2 ′2 X 1 2 + X 1 2 X 2 2 + 2 X M 2 X 1 X 2
  • [0026]
    Therefore, when at or near the resonance condition:
  • [0000]

    ω=ω020→X1=0, X2=0
  • [0000]
    P 2 = X M 2 R 1 U s 2 R 1 ′2 R 2 ′2 + 2 X M 2 R 1 R 2 + X M 4 = X M 2 R L ( R 1 R 2 + X M 2 ) 2 U s 2 P 2 = ω 0 2 M 2 R L ( R s + R 1 ) 2 ( R 1 + R 2 ) 2 + 2 ω 0 2 M 2 ( R s + R 1 ) ( R L + R 2 ) + ω 0 4 M 4 U s 2 P 2 = ω 0 2 M 2 R L ( ( R s + R 1 ) ( R 1 + R 2 ) + ω 0 2 M 2 ) 2 U s 2
  • [0000]
    Showing that the power transfer is inversely proportional to several variables, including series resistances.
  • [0027]
    Mutual inductance in terms of coupling factors and inductions:
  • [0000]
    M = k L 1 L 2 P 2 = ω 0 2 k 2 L 1 L 2 R L ( ( R s + R 1 ) ( R 1 + R 2 ) + ω 0 2 k 2 L 1 L 2 ) 2 U s 2 = k 2 ω 0 L 1 ω 0 L 2 ( R s + R M ) ( R 1 + R 2 ) ( 1 + k 2 ω 0 L 1 ω 0 L 2 ( R s + R M ) ( R 1 + R 2 ) ) 2 U s 2 R L ( R s + R 1 ) ( R L + R 2 ) P 2 = k 2 Q L 1 Q L 2 ( 1 + k 2 Q L 1 Q L 2 ) 2 R L ( R s + R 1 ) ( R L + R 2 ) U s 2
  • [0028]
    The power output is proportional to the square of the input power, as described above. However, there is a maximum input power beyond which no further output power will be produced. These values are explained below. The maximum input power P1max is expressed as:
  • [0000]
    P 1 , max = U s 2 R s + R in , min = Re { U s I 1 * } ;
  • [0000]
    Rin,min: permissible input resistance
    Efficiency relative to maximum input power:
  • [0000]
    η = P 2 P 1 , max = P 2 ( U s 2 ) P 1 , max
  • [0000]
    Under resonance condition ω=ω120:
  • [0000]
    η = ω 0 2 M 2 R L ( R s + R in , min ) [ ( R s + R 1 ) ( R 1 + R 2 ) + ω 0 2 M 2 ] 2
  • [0000]
    Equation for input power (P1) under the resonance condition is therefore.
  • [0000]
    P 1 = P 2 η = ω 0 2 M 2 R L [ ( R s + R 1 ) ( R 1 + R 2 ) + ω 0 2 M 2 ] ( R L + R 2 ) [ ( R s + R 2 ) ( R L + R 2 ) + ω 0 0 M 2 ] 2 ω 0 2 M 2 R L U s 2 P 1 = R L + R 2 ( R s + R 1 ) ( R L + R 2 ) + 0 2 M 2 U S 2 For ( R s + R M ) ( R L + R 2 ) >> ω 0 2 M 2 : P 1 U S 2 ( R s + R 1 )
  • [0029]
    The current ratio between input and induced currents can be expressed as
  • [0000]
    I 2 I 1 = z M U s ( z 1 z 2 - z n 2 ) ( z 1 z 2 - z M 2 ) z 2 U s = z M z 2 = j ω M R L + R 2 + j ( ω L 2 - 1 ω C 2 ) at ω = ω 0 = 1 L 2 C 2 I 2 I 1 = j ω M R 1 + R 2 avg . { I 2 I 1 } = π 2
  • [0000]
    Weak coupling: R1+R2>|jωM|
  • [0000]

    →I2<I1
  • [0000]
    Strong coupling: R1+R2<|jωM|
  • [0000]

    →I2>I1
  • [0000]
    Input current I: (under resonance condition)
  • [0000]
    I 1 = P 1 U S = ( R 1 + R 2 ) U s ( R S + R 1 ) ( R L + R 2 ) + ω 0 2 M 2 I 1 = ( R L + R 2 ) ( R s + R 1 ) ( R L + R 2 ) + ω 0 2 M 2 U s
  • [0000]
    Output current I2: (under resonance condition)
  • [0000]
    I 2 = j ω M ( R s + R 1 ) ( R L + R 2 ) + ω 0 2 M 2 U s
  • [0030]
    Maximizing transfer efficiency and output power (P2)
  • [0031]
    can be calculated according to the transfer efficiency equation:
  • [0000]
    η = P 2 P 1 = ω 2 M 2 R L ( R s + R n ) [ ( R L + R 2 ) 2 + ( ω L 2 - 1 ω C 2 + X L ) 2 ] + ω 2 M 2 ( R L + R 2 )
  • [0000]
    After reviewing this equation, an embodiment forms circuits that are based on observations about the nature of how to maximize efficiency in such a system.
  • Conclusion 1)
  • [0032]
    η(L2, C2, XL) reaches maximum for
  • [0000]
    ω L 2 - 1 ω C 2 + X L = 0
  • [0000]
    That is, efficiency for any L, C, X at the receiver is maximum when that equation is met.
    Transfer efficiency wide resonance condition:
  • [0000]
    η = P 2 P 1 ω = ω 0 = ω 0 2 M 2 [ ( R s + R n ) ( R L + R 2 ) + ω 0 2 M 2 ] R 1 ( R L + R 2 )
  • Conclusion 2)
  • [0033]
    To maximise η Rs should be Rs<<R1
    That is, for maximum efficiency, the source resistance Rs needs to be much lower than the series resistance, e.g., 1/50, or 1/100th or less
    Transfer efficiency under resonance and weak coupling condition:
  • [0000]
    ( R s + R n ) ( R L + R 2 ) >> ω 0 2 M 2 η ω 0 2 M 2 R L ( R s + R n ) ( R L + R 2 ) 2
  • Maximising η(RL):
  • [0034]
    η R L = ω 0 2 M 2 R s + R 1 ( R L + R 2 ) - 2 R L ( R L + R 2 ) 3 = 0 R L = R 2
  • Conclusion 3)
  • [0035]
    η reaches maximum for RL=R2 under weak coupling condition.
    That is, when there is weak coupling, efficiency is maximum when the resistance of the load matches the series resistance of the receiver.
    Transfer efficiency under resonance condition.
    Optimising RL to achieve max. η
  • [0000]
    η R L = 0 ; R L ω 0 2 M 2 R L ( R s + R 1 ) R 1 ( R L + R 2 ) 2 + ω 0 2 M 2 ( R L + R 2 ) u v u v - v u v 2 = 0 u = ω 0 2 M 2 R L ; u = ω 0 2 M 2 v = R 1 ( R L + R 2 ) 2 + ω 0 2 M 2 ( R 1 + R 2 ) u v - v u = 0 v - 2 R 1 ( R L + R 2 ) + ω 0 2 M 2 u v - v u = ? ( 2 R 1 ( R L + R 2 ) + ω 0 2 M 2 ) - ( R 1 ( R 1 + R 2 ) 2 + ω 0 2 M 2 ( R L + R 2 ) ) ? = 0 = 2 R 1 R L ( R L + R 2 ) + ω 0 2 M 2 R L - R 1 ( R L + R 2 ) 2 - ω 0 2 M 2 ( R L + R 2 ) = 0 = ? + ? + ? - ? - ? - ? - ? - ? = 0 = ( 1 R 1 - R 1 ) R L 2 - R 1 R 2 2 - ω 0 2 M 2 R 2 = 0 R L 2 = R 1 R 2 2 + ω 0 2 M 2 R 2 R 1 R L = ( R s + R 1 ) R 2 2 + ω 0 2 M 2 R 2 ( R s + R 1 ) = R 2 ( R s + R 1 ) + ω 0 2 M 2 / R 2 ( R s + R 1 ) R L , opt = R 2 1 + ω 0 2 M 2 ( R s + R 1 ) R 2 ? indicates text missing or illegible when filed
  • [0000]
    Weak coupling condition ω0 2M2<<(Rs+R1)R2
  • Conclusion 4)
  • [0036]
    There exists an optimum RL>R2 maximising η
    Output power P2:
  • [0000]
    P 2 = X M 2 R 1 U s w ( R 1 R 2 + X M 2 ) 2 + R 1 ′2 X 2 2 + R 2 ′2 X 1 2 + X 1 2 X 2 2 + 2 X M 2 X 2 X 2
  • Conclusion 5)
  • [0037]
    Output power P2(X1, X2) reaches maximum for
  • [0000]
    X 1 = ω L 1 - 1 ω C 1 + X s = 0 X 2 = ω L 2 - 1 ω C 2 + X L = 0
  • [0000]
    that is, when there is a resonance condition at both the primary and the secondary.
    Output power P2 wide resonance condition:
  • [0000]
    P 2 = ω 0 2 M 2 R L [ ( P s + R 1 ) ( R 1 + R 2 ) + ω 0 2 M 2 ] 2 U s 2
  • Conclusion 6)
  • [0038]
    To maximize P2, Rs should be Rs<<R1
    Output power P2 for the wide resonance and weak coupling condition:
  • [0000]

    (R s +R 1)(R L +R 2)>>ω0 2 M 2
  • [0000]
    P 2 ω 0 2 M 2 R L ( R s + R 1 ) 2 + ( R L + R 2 ) 1 U s 2
  • Conclusion 7)
  • [0039]
    P2 (RL) reaches maximum for RL=R2 (see conclusion 3)
    For each of the above, the >> or << can represent much greater, much less, e.g., 20 or 1/20 or less, or 50 or 1/50th or less or 100 or 1/100th or less.
    The value RL can also be optimized to maximize P2:
  • [0000]
    P 2 R L = 0 u v - v u v 2 = 0 u = ω 0 2 M 2 R L ; u = ω 0 2 M 2 v = [ ( R 1 ) ( R L + R 2 ) + ω 0 2 M 2 ] 2 v = 2 [ R 1 ( R L + R 2 ) + ω 0 2 M 2 ] R 1 ? R L 2 [ R 1 ( R 1 + R 2 ) + ω 0 2 M 2 ] R 1 - [ R 1 ( R L + R 2 ) + ω 0 2 M 2 ] 2 ? = 0 2 R L ( R 1 ′2 R L + R 1 ′2 R 2 ) + 1 R L ω 0 2 M 2 R 1 - [ R 1 R L + R 1 R 2 + ω 0 2 M 2 ] 2 = 0 2 ? + ? + ? - ? - R 1 ′2 R 2 2 - ω 0 2 M 4 - ? - 2 ? - 2 R 1 R 2 ω 0 2 M 2 = 0 = ( 2 R 1 ′2 - R 1 ′2 ) R L 2 - R 1 ′2 R 2 2 - 2 R 1 R 2 ω 0 2 M 2 - ω 0 2 M 4 = 0 = R 1 ′2 R L 2 - ( R 1 R 2 + ω 0 2 M 2 ) 2 = 0 R L 2 = ( R 1 R 2 + ω 0 2 M 2 ) 2 R 1 ′2 R L , opt = R 1 R 2 + ω 0 2 M 2 R 1 = R 2 ( 1 + ω 0 2 M 2 ( R s + R 1 ) R 2 ) R L , opt = R 2 ( 1 + ω 0 2 M 2 ( R s + R 1 ) R 2 ) Weak coupling : R L , opt > R 2 ? indicates text missing or illegible when filed
  • Conclusion 8)
  • [0040]
    There exists an optimum RL>R2 maximising P2. This R1opt differs from the R1,opt maximising η.
    One embodiment operates by optimizing one or more of these values, to form an optimum value.
  • [0041]
    Inductive coupling is shown with reference to FIGS. 3, 4 FIG. 5 illustrates the Inductance of a multi-turn circular loop coil
  • [0000]
    R m = R 0 + R 1 2
  • [0000]
    Wheeler formula (empirical) L = 0.8 R m 2 N 2 6 R m + 9 w + 10 ( ( R 0 - R 1 ) [Wheeler, H. A., “Simple inductance formulas for radio coils”. Proc. IRE Vol 16, pp. 1328-1400, October 1928.]
    Note: this i accurate if all three
    terms in denominator are about equal.
    Conversion to H, m units: [L]μH
    L = 0.8 R m 2 2 N 1 10 - 6 6 R m + 9 w + 10 ( R 0 - R 1 ) L = 0.8 R m 2 2 N 2 10 - 6 6 R m + 9 w + 10 ( R 0 - R 1 ) [Rm, Ri, R0, ω] = inch 1 m = 10 00 - 154 inch 1H = 106 μH [L] = H [RmR0R1ω] = m
  • [0042]
    In standard form:
  • [0000]
    L = μ 0 A m N 2 K c ; A m = π R m 2 μ 0 = 4 π 10 - 7 L = 0.8 10 - 6 π R m 2 N 2 4 π 10 - 7 π 4 π 10 - 7 ( 6 R m + 9 w + 10 ( R 0 - R 1 ) ) L = μ 0 A m N 2 0.8 ? 10 4 π 2 ? ( 6 R m + 9 w + 10 ( R 0 - R 1 ) ) 1 K c R m = A m π K c = π 2 25.4 ( 6 A m π + 9 w + 10 ( R 0 - R 1 ) ) 2 1000 K c 1 8 ( 6 A m π + 9 w + 10 ( R 0 - R 1 ) ) L = μ 0 A m N 2 K c ; A m = ( ( R 0 + R 1 ) 2 ) 2 π [ L ] = H ? indicates text missing or illegible when filed
  • [0043]
    The inductance of a single-turn circular loop is given as:
  • [0000]
    K c = R m π [ 8 R m 6 - 2 ] L = μ 0 A m K c ; A m = R m 2 π [ L ] = H
  • [0000]
    where:
  • [0044]
    Rm: mean radius in m
  • [0045]
    b: wire radius in m,
  • [0046]
    For a Numerical example:
  • [0047]
    R1=0.13 m
  • [0048]
    R0=0.14 m
  • [0049]
    ω=0.01 m
  • [0050]
    N=36
  • [0051]
    →L=0.746 mH
  • [0052]
    The measured inductance
  • [0000]

    Lmeas=0.085 mH
  • [0053]
    The model fraction of Wheeler formula for inductors of similar geometry, e.g, with similar radius and width ratios is:
  • [0000]
    K c = 1 8 ( 5 A m π + 9 w + 10 ( R 0 - R 1 ) ) D = W 2 + ( R 0 - R 1 ) 2 R m = R 0 + R 1 2
  • [0054]
    Using a known formula from Goddam, V. R., which is valid for
  • [0000]

    w>(R 0 −R 1)
  • [0000]
    L = 0.03193 R m N 2 2.303 ( 1 + w 2 32 R m 2 + D 2 96 R m 2 ) log ( 8 R m D ) -
  • [0000]
    1w H,m units:
  • [0000]
    L = μ 0 R m N 2 ( 1 + w 2 32 R m 2 + D 2 96 R m 2 ) n ( 8 R m D ) -
  • [0055]
    Example 1:
  • [0000]
    R1 = 0.13 m R0 = 0.14 m W = 0.01 m N = 36 L = 757 μH Ratio : W R 0 - R 1 = 1 → y1 = 0.8483    y2 = 0.816 From [Terman, F.]
  • [0056]
    Example 2: (given in [Goddam, V. R.]
  • [0000]
    R0 = 8.175 inches R1 = 7.875 inches W = 2 inches N = 57 y1 = 0.6310 y2 = 0.142 → L = 2.5 mH (2.36 mH) Ratio : 2 R 0 - R 1 = 2 0.3 = 6.667 or R 0 - R 1 W = 0.3 2 = 0.15
  • [0057]
    where Goddam, V. R. is the Thesis Masters Louisiana State University, 2005, and Terman, F. is the Radio Engineers Handbook, McGraw Hill, 1943.
  • [0058]
    Any of these values can be used to optimize wireless power transfer between a source and receiver.
  • [0059]
    From the above, it can be seen that there are really two different features to consider and optimize in wireless transfer circuits. A first feature relates to the way in which efficiency of power transfer is optimized. A second feature relates to maximizing the received amount of power—independent of the efficiency.
  • [0060]
    One embodiment, determines both maximum efficiency, and maximum received power, and determines which one to use, and/or how to balance between the two.
  • [0061]
    In one embodiment, rules are set. For example, the rules may specify:
  • [0062]
    Rule 1—Maximize efficiency, unless power transfer will be less than 1 watt. If so, increase power transfer at cost of less efficiency.
  • [0063]
    Rule 2—Maximize power transfer, unless efficiency becomes less than 30%.
  • [0064]
    Any of these rules may be used as design rules, or as rules to vary parameters of the circuit during its operation. In one embodiment, the circuit values are adaptively changes based on operational parameters. This may use variable components, such as variable resistors, capacitors, inductors, and/or FPGAs for variation in circuit values.
  • [0065]
    Although only a few embodiments have been disclosed in detail above, other embodiments are possible and the inventors intend these to be encompassed within this specification. The specification describes specific examples to accomplish a more general goal that may be accomplished in another way. This disclosure is intended to be exemplary, and the claims are intended to cover any modification or alternative which might be predictable to a person having ordinary skill in the art. For example, other sizes, materials and connections can be used. Other structures can be used to receive the magnetic field. In general, an electric field can be used in place of the magnetic field, as the primary coupling mechanism. Other kinds of antennas can be used. Also, the inventors intend that only those claims which use the-words “means for” are intended to be interpreted under 35 USC 112, sixth paragraph. Moreover, no limitations from the specification are intended to be read into any claims, unless those limitations are expressly included in the claims.
  • [0066]
    Where a specific numerical value is mentioned herein, it should be considered that the value may be increased or decreased by 20%, while still staying within the teachings of the present application, unless some different range is specifically mentioned. Where a specified logical sense is used, the opposite logical sense is also intended to be encompassed.
Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US5889384 *Feb 20, 1997Mar 30, 1999Ericsson Inc.Power transfer and voltage level conversion for a battery-powered electronic device
US6483202 *Nov 16, 1998Nov 19, 2002Auckland Uniservices LimitedControl of inductive power transfer pickups
US6515878 *Aug 7, 1998Feb 4, 2003Meins Juergen G.Method and apparatus for supplying contactless power
US7159774 *Dec 16, 2005Jan 9, 2007The United States Of America As Represented By The Administrator Of The National Aeronautics And Space AdministrationMagnetic field response measurement acquisition system
US7639514 *Mar 12, 2007Dec 29, 2009Access Business Group International LlcAdaptive inductive power supply
US7741734 *Jul 5, 2006Jun 22, 2010Massachusetts Institute Of TechnologyWireless non-radiative energy transfer
US7825543 *Mar 26, 2008Nov 2, 2010Massachusetts Institute Of TechnologyWireless energy transfer
US7868482 *Oct 23, 2006Jan 11, 2011Powercast CorporationMethod and apparatus for high efficiency rectification for various loads
US7939886 *Nov 22, 2005May 10, 2011Shindengen Electric Manufacturing Co., Ltd.Trench gate power semiconductor device
US20070222542 *Jul 5, 2006Sep 27, 2007Joannopoulos John DWireless non-radiative energy transfer
US20070228833 *May 11, 2005Oct 4, 2007Stevens Michael CControlling Inductive Power Transfer Systems
US20070285325 *Jun 7, 2006Dec 13, 2007St Clair John QuincyChi energy amplifier
US20080054638 *Aug 30, 2007Mar 6, 2008Powercast CorporationHybrid power harvesting and method
US20080067874 *Sep 14, 2007Mar 20, 2008Ryan TsengMethod and apparatus for wireless power transmission
US20090001941 *Jun 29, 2007Jan 1, 2009Microsoft CorporationInductive Powering Surface for Powering Portable Devices
US20090067208 *Sep 10, 2008Mar 12, 2009Donald Corey MartinMethod and apparatus for providing power
US20090108805 *Oct 30, 2007Apr 30, 2009City University Of Hong KongLocalized charging, load identification and bi-directional communication methods for a planar inductive battery charging system
US20090160261 *Dec 19, 2007Jun 25, 2009Nokia CorporationWireless energy transfer
US20090167449 *Oct 13, 2008Jul 2, 2009Nigel Power, LlcWireless Power Transfer using Magneto Mechanical Systems
US20090243394 *Mar 28, 2008Oct 1, 2009Nigelpower, LlcTuning and Gain Control in Electro-Magnetic power systems
US20090284083 *May 14, 2009Nov 19, 2009Aristeidis KaralisWireless energy transfer, including interference enhancement
US20090284245 *Nov 7, 2008Nov 19, 2009Qualcomm IncorporatedWireless power transfer for appliances and equipments
US20090302933 *Apr 28, 2006Dec 10, 2009Auckland Uniservices LimitedTuning methods and apparatus for inductively coupled power transfer (ICPT) systems
US20090308933 *Nov 13, 2007Dec 17, 2009Semiconductor Energy Laboratory Co., Ltd.Wireless power receiving device
US20100109445 *Nov 6, 2009May 6, 2010Kurs Andre BWireless energy transfer systems
US20100117456 *Jan 15, 2010May 13, 2010Aristeidis KaralisApplications of wireless energy transfer using coupled antennas
US20100164296 *Dec 28, 2009Jul 1, 2010Kurs Andre BWireless energy transfer using variable size resonators and system monitoring
US20100181845 *Mar 30, 2010Jul 22, 2010Ron FiorelloTemperature compensation in a wireless transfer system
US20100181961 *Nov 10, 2009Jul 22, 2010Qualcomm IncorporatedAdaptive power control for wireless charging
US20100201310 *Apr 10, 2009Aug 12, 2010Broadcom CorporationWireless power transfer system
US20100222010 *Jan 28, 2010Sep 2, 2010Qualcomm IncorporatedAntenna sharing for wirelessly powered devices
US20100231053 *May 26, 2010Sep 16, 2010Aristeidis KaralisWireless power range increase using parasitic resonators
US20100277121 *Apr 29, 2010Nov 4, 2010Hall Katherine LWireless energy transfer between a source and a vehicle
US20100289449 *Dec 18, 2008Nov 18, 2010Harri Heikki EloWireless energy transfer
US20110095618 *Apr 13, 2010Apr 28, 2011Schatz David AWireless energy transfer using repeater resonators
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US7741734Jul 5, 2006Jun 22, 2010Massachusetts Institute Of TechnologyWireless non-radiative energy transfer
US7825543Mar 26, 2008Nov 2, 2010Massachusetts Institute Of TechnologyWireless energy transfer
US8022576Mar 31, 2009Sep 20, 2011Massachusetts Institute Of TechnologyWireless non-radiative energy transfer
US8035255Nov 6, 2009Oct 11, 2011Witricity CorporationWireless energy transfer using planar capacitively loaded conducting loop resonators
US8076800Mar 31, 2009Dec 13, 2011Massachusetts Institute Of TechnologyWireless non-radiative energy transfer
US8076801May 14, 2009Dec 13, 2011Massachusetts Institute Of TechnologyWireless energy transfer, including interference enhancement
US8084889Mar 31, 2009Dec 27, 2011Massachusetts Institute Of TechnologyWireless non-radiative energy transfer
US8097983May 8, 2009Jan 17, 2012Massachusetts Institute Of TechnologyWireless energy transfer
US8106539Mar 11, 2010Jan 31, 2012Witricity CorporationWireless energy transfer for refrigerator application
US8169185May 7, 2008May 1, 2012Mojo Mobility, Inc.System and method for inductive charging of portable devices
US8304935Dec 28, 2009Nov 6, 2012Witricity CorporationWireless energy transfer using field shaping to reduce loss
US8324759Dec 28, 2009Dec 4, 2012Witricity CorporationWireless energy transfer using magnetic materials to shape field and reduce loss
US8362651Oct 1, 2009Jan 29, 2013Massachusetts Institute Of TechnologyEfficient near-field wireless energy transfer using adiabatic system variations
US8395282Mar 31, 2009Mar 12, 2013Massachusetts Institute Of TechnologyWireless non-radiative energy transfer
US8395283Dec 16, 2009Mar 12, 2013Massachusetts Institute Of TechnologyWireless energy transfer over a distance at high efficiency
US8400017Nov 5, 2009Mar 19, 2013Witricity CorporationWireless energy transfer for computer peripheral applications
US8400018Dec 16, 2009Mar 19, 2013Massachusetts Institute Of TechnologyWireless energy transfer with high-Q at high efficiency
US8400019Dec 16, 2009Mar 19, 2013Massachusetts Institute Of TechnologyWireless energy transfer with high-Q from more than one source
US8400020Dec 16, 2009Mar 19, 2013Massachusetts Institute Of TechnologyWireless energy transfer with high-Q devices at variable distances
US8400021Dec 16, 2009Mar 19, 2013Massachusetts Institute Of TechnologyWireless energy transfer with high-Q sub-wavelength resonators
US8400022Dec 23, 2009Mar 19, 2013Massachusetts Institute Of TechnologyWireless energy transfer with high-Q similar resonant frequency resonators
US8400023Dec 23, 2009Mar 19, 2013Massachusetts Institute Of TechnologyWireless energy transfer with high-Q capacitively loaded conducting loops
US8400024Dec 30, 2009Mar 19, 2013Massachusetts Institute Of TechnologyWireless energy transfer across variable distances
US8410636Dec 16, 2009Apr 2, 2013Witricity CorporationLow AC resistance conductor designs
US8441154Oct 28, 2011May 14, 2013Witricity CorporationMulti-resonator wireless energy transfer for exterior lighting
US8461719Sep 25, 2009Jun 11, 2013Witricity CorporationWireless energy transfer systems
US8461720Dec 28, 2009Jun 11, 2013Witricity CorporationWireless energy transfer using conducting surfaces to shape fields and reduce loss
US8461721Dec 29, 2009Jun 11, 2013Witricity CorporationWireless energy transfer using object positioning for low loss
US8461722Dec 29, 2009Jun 11, 2013Witricity CorporationWireless energy transfer using conducting surfaces to shape field and improve K
US8466583Nov 7, 2011Jun 18, 2013Witricity CorporationTunable wireless energy transfer for outdoor lighting applications
US8471410Dec 30, 2009Jun 25, 2013Witricity CorporationWireless energy transfer over distance using field shaping to improve the coupling factor
US8476788Dec 29, 2009Jul 2, 2013Witricity CorporationWireless energy transfer with high-Q resonators using field shaping to improve K
US8482158Dec 28, 2009Jul 9, 2013Witricity CorporationWireless energy transfer using variable size resonators and system monitoring
US8487480Dec 16, 2009Jul 16, 2013Witricity CorporationWireless energy transfer resonator kit
US8497601Apr 26, 2010Jul 30, 2013Witricity CorporationWireless energy transfer converters
US8552592Feb 2, 2010Oct 8, 2013Witricity CorporationWireless energy transfer with feedback control for lighting applications
US8569914Dec 29, 2009Oct 29, 2013Witricity CorporationWireless energy transfer using object positioning for improved k
US8587153Dec 14, 2009Nov 19, 2013Witricity CorporationWireless energy transfer using high Q resonators for lighting applications
US8587155Mar 10, 2010Nov 19, 2013Witricity CorporationWireless energy transfer using repeater resonators
US8598743May 28, 2010Dec 3, 2013Witricity CorporationResonator arrays for wireless energy transfer
US8598745Oct 6, 2010Dec 3, 2013Tdk CorporationWireless power feeder and wireless power transmission system
US8618696Feb 21, 2013Dec 31, 2013Witricity CorporationWireless energy transfer systems
US8629578Feb 21, 2013Jan 14, 2014Witricity CorporationWireless energy transfer systems
US8629652May 23, 2011Jan 14, 2014Mojo Mobility, Inc.Power source, charging system, and inductive receiver for mobile devices
US8629654Apr 9, 2012Jan 14, 2014Mojo Mobility, Inc.System and method for inductive charging of portable devices
US8643326Jan 6, 2011Feb 4, 2014Witricity CorporationTunable wireless energy transfer systems
US8664803Oct 14, 2011Mar 4, 2014Tdk CorporationWireless power feeder, wireless power receiver, and wireless power transmission system
US8667452Nov 5, 2012Mar 4, 2014Witricity CorporationWireless energy transfer modeling tool
US8669676Dec 30, 2009Mar 11, 2014Witricity CorporationWireless energy transfer across variable distances using field shaping with magnetic materials to improve the coupling factor
US8669677Sep 30, 2011Mar 11, 2014Tdk CorporationWireless power feeder, wireless power receiver, and wireless power transmission system
US8686598Dec 31, 2009Apr 1, 2014Witricity CorporationWireless energy transfer for supplying power and heat to a device
US8692410Dec 31, 2009Apr 8, 2014Witricity CorporationWireless energy transfer with frequency hopping
US8692412Mar 30, 2010Apr 8, 2014Witricity CorporationTemperature compensation in a wireless transfer system
US8716903Mar 29, 2013May 6, 2014Witricity CorporationLow AC resistance conductor designs
US8723366Mar 10, 2010May 13, 2014Witricity CorporationWireless energy transfer resonator enclosures
US8729736Apr 7, 2011May 20, 2014Tdk CorporationWireless power feeder and wireless power transmission system
US8729737Feb 8, 2012May 20, 2014Witricity CorporationWireless energy transfer using repeater resonators
US8742627Jul 8, 2011Jun 3, 2014Tdk CorporationWireless power feeder
US8760007Dec 16, 2009Jun 24, 2014Massachusetts Institute Of TechnologyWireless energy transfer with high-Q to more than one device
US8760008Dec 30, 2009Jun 24, 2014Massachusetts Institute Of TechnologyWireless energy transfer over variable distances between resonators of substantially similar resonant frequencies
US8766485Dec 30, 2009Jul 1, 2014Massachusetts Institute Of TechnologyWireless energy transfer over distances to a moving device
US8772971Dec 30, 2009Jul 8, 2014Massachusetts Institute Of TechnologyWireless energy transfer across variable distances with high-Q capacitively-loaded conducting-wire loops
US8772972Dec 30, 2009Jul 8, 2014Massachusetts Institute Of TechnologyWireless energy transfer across a distance to a moving device
US8772973Aug 20, 2010Jul 8, 2014Witricity CorporationIntegrated resonator-shield structures
US8772977Apr 28, 2011Jul 8, 2014Tdk CorporationWireless power feeder, wireless power transmission system, and table and table lamp using the same
US8791599Dec 30, 2009Jul 29, 2014Massachusetts Institute Of TechnologyWireless energy transfer to a moving device between high-Q resonators
US8800738Jun 28, 2011Aug 12, 2014Tdk CorporationWireless power feeder and wireless power receiver
US8805530Jun 2, 2008Aug 12, 2014Witricity CorporationPower generation for implantable devices
US8829725Mar 18, 2011Sep 9, 2014Tdk CorporationWireless power feeder, wireless power receiver, and wireless power transmission system
US8829726Apr 5, 2011Sep 9, 2014Tdk CorporationWireless power feeder and wireless power transmission system
US8829727Apr 28, 2011Sep 9, 2014Tdk CorporationWireless power feeder, wireless power transmission system, and table and table lamp using the same
US8829729May 18, 2011Sep 9, 2014Tdk CorporationWireless power feeder, wireless power receiver, and wireless power transmission system
US8836172Nov 15, 2012Sep 16, 2014Massachusetts Institute Of TechnologyEfficient near-field wireless energy transfer using adiabatic system variations
US8847548Aug 7, 2013Sep 30, 2014Witricity CorporationWireless energy transfer for implantable devices
US8875086Dec 31, 2013Oct 28, 2014Witricity CorporationWireless energy transfer modeling tool
US8890470Jun 10, 2011Nov 18, 2014Mojo Mobility, Inc.System for wireless power transfer that supports interoperability, and multi-pole magnets for use therewith
US8896264Dec 7, 2012Nov 25, 2014Mojo Mobility, Inc.Inductive charging with support for multiple charging protocols
US8901776Apr 18, 2011Dec 2, 2014Tdk CorporationWireless power feeder, wireless power receiver, and wireless power transmission system
US8901778Oct 21, 2011Dec 2, 2014Witricity CorporationWireless energy transfer with variable size resonators for implanted medical devices
US8901779Oct 21, 2011Dec 2, 2014Witricity CorporationWireless energy transfer with resonator arrays for medical applications
US8901881Dec 7, 2012Dec 2, 2014Mojo Mobility, Inc.Intelligent initiation of inductive charging process
US8907531Oct 21, 2011Dec 9, 2014Witricity CorporationWireless energy transfer with variable size resonators for medical applications
US8912687Nov 3, 2011Dec 16, 2014Witricity CorporationSecure wireless energy transfer for vehicle applications
US8922066Oct 17, 2011Dec 30, 2014Witricity CorporationWireless energy transfer with multi resonator arrays for vehicle applications
US8928276Mar 23, 2012Jan 6, 2015Witricity CorporationIntegrated repeaters for cell phone applications
US8933589Feb 7, 2012Jan 13, 2015The Gillette CompanyWireless power transfer using separately tunable resonators
US8933594Oct 18, 2011Jan 13, 2015Witricity CorporationWireless energy transfer for vehicles
US8937408Apr 20, 2011Jan 20, 2015Witricity CorporationWireless energy transfer for medical applications
US8946938Oct 18, 2011Feb 3, 2015Witricity CorporationSafety systems for wireless energy transfer in vehicle applications
US8947047Dec 7, 2012Feb 3, 2015Mojo Mobility, Inc.Efficiency and flexibility in inductive charging
US8947186Feb 7, 2011Feb 3, 2015Witricity CorporationWireless energy transfer resonator thermal management
US8957549Nov 3, 2011Feb 17, 2015Witricity CorporationTunable wireless energy transfer for in-vehicle applications
US8963488Oct 6, 2011Feb 24, 2015Witricity CorporationPosition insensitive wireless charging
US8970069Mar 28, 2011Mar 3, 2015Tdk CorporationWireless power receiver and wireless power transmission system
US8981597Apr 15, 2011Mar 17, 2015Tdk CorporationWireless power feeder, wireless power receiver, and wireless power transmission system
US9035499Oct 19, 2011May 19, 2015Witricity CorporationWireless energy transfer for photovoltaic panels
US9058928Dec 28, 2010Jun 16, 2015Tdk CorporationWireless power feeder and wireless power transmission system
US9065286Jun 12, 2014Jun 23, 2015Massachusetts Institute Of TechnologyWireless non-radiative energy transfer
US9065423Sep 14, 2011Jun 23, 2015Witricity CorporationWireless energy distribution system
US9093853Jan 30, 2012Jul 28, 2015Witricity CorporationFlexible resonator attachment
US9095729Jan 20, 2012Aug 4, 2015Witricity CorporationWireless power harvesting and transmission with heterogeneous signals
US9101777Aug 29, 2011Aug 11, 2015Witricity CorporationWireless power harvesting and transmission with heterogeneous signals
US9105959Sep 4, 2012Aug 11, 2015Witricity CorporationResonator enclosure
US9106083Dec 10, 2012Aug 11, 2015Mojo Mobility, Inc.Systems and method for positioning freedom, and support of different voltages, protocols, and power levels in a wireless power system
US9106203Nov 7, 2011Aug 11, 2015Witricity CorporationSecure wireless energy transfer in medical applications
US9112362Dec 10, 2012Aug 18, 2015Mojo Mobility, Inc.Methods for improved transfer efficiency in a multi-dimensional inductive charger
US9112363Dec 10, 2012Aug 18, 2015Mojo Mobility, Inc.Intelligent charging of multiple electric or electronic devices with a multi-dimensional inductive charger
US9112364Dec 10, 2012Aug 18, 2015Mojo Mobility, Inc.Multi-dimensional inductive charger and applications thereof
US9143010Dec 21, 2011Sep 22, 2015Tdk CorporationWireless power transmission system for selectively powering one or more of a plurality of receivers
US9160203Oct 6, 2011Oct 13, 2015Witricity CorporationWireless powered television
US9178369Jan 17, 2012Nov 3, 2015Mojo Mobility, Inc.Systems and methods for providing positioning freedom, and support of different voltages, protocols, and power levels in a wireless power system
US9184595Feb 13, 2010Nov 10, 2015Witricity CorporationWireless energy transfer in lossy environments
US9246336Jun 22, 2012Jan 26, 2016Witricity CorporationResonator optimizations for wireless energy transfer
US9276437Jan 28, 2015Mar 1, 2016Mojo Mobility, Inc.System and method that provides efficiency and flexiblity in inductive charging
US9287607Jul 31, 2012Mar 15, 2016Witricity CorporationResonator fine tuning
US9306635Jan 28, 2013Apr 5, 2016Witricity CorporationWireless energy transfer with reduced fields
US9318257Oct 18, 2012Apr 19, 2016Witricity CorporationWireless energy transfer for packaging
US9318898Jun 25, 2015Apr 19, 2016Witricity CorporationWireless power harvesting and transmission with heterogeneous signals
US9318922Mar 15, 2013Apr 19, 2016Witricity CorporationMechanically removable wireless power vehicle seat assembly
US9343922Jun 27, 2012May 17, 2016Witricity CorporationWireless energy transfer for rechargeable batteries
US9356659Mar 14, 2013May 31, 2016Mojo Mobility, Inc.Chargers and methods for wireless power transfer
US9369182Jun 21, 2013Jun 14, 2016Witricity CorporationWireless energy transfer using variable size resonators and system monitoring
US9384885Aug 6, 2012Jul 5, 2016Witricity CorporationTunable wireless power architectures
US9396867Apr 14, 2014Jul 19, 2016Witricity CorporationIntegrated resonator-shield structures
US9404954Oct 21, 2013Aug 2, 2016Witricity CorporationForeign object detection in wireless energy transfer systems
US9421388Aug 7, 2014Aug 23, 2016Witricity CorporationPower generation for implantable devices
US9442172Sep 10, 2012Sep 13, 2016Witricity CorporationForeign object detection in wireless energy transfer systems
US9444265May 22, 2012Sep 13, 2016Massachusetts Institute Of TechnologyWireless energy transfer
US9444520Jul 19, 2013Sep 13, 2016Witricity CorporationWireless energy transfer converters
US9449757Nov 18, 2013Sep 20, 2016Witricity CorporationSystems and methods for wireless power system with improved performance and/or ease of use
US9450421Feb 24, 2015Sep 20, 2016Massachusetts Institute Of TechnologyWireless non-radiative energy transfer
US9450422Mar 24, 2015Sep 20, 2016Massachusetts Institute Of TechnologyWireless energy transfer
US9461501Dec 19, 2013Oct 4, 2016Mojo Mobility, Inc.Power source, charging system, and inductive receiver for mobile devices
US9465064Oct 21, 2013Oct 11, 2016Witricity CorporationForeign object detection in wireless energy transfer systems
US9496719Sep 25, 2014Nov 15, 2016Witricity CorporationWireless energy transfer for implantable devices
US9496732Mar 14, 2013Nov 15, 2016Mojo Mobility, Inc.Systems and methods for wireless power transfer
US9509147Mar 8, 2013Nov 29, 2016Massachusetts Institute Of TechnologyWireless energy transfer
US9515494Apr 9, 2015Dec 6, 2016Witricity CorporationWireless power system including impedance matching network
US9515495Oct 30, 2015Dec 6, 2016Witricity CorporationWireless energy transfer in lossy environments
US9544683Oct 17, 2013Jan 10, 2017Witricity CorporationWirelessly powered audio devices
US9577436Jun 6, 2011Feb 21, 2017Witricity CorporationWireless energy transfer for implantable devices
US9577440May 25, 2011Feb 21, 2017Mojo Mobility, Inc.Inductive power source and charging system
US9584189Jun 21, 2013Feb 28, 2017Witricity CorporationWireless energy transfer using variable size resonators and system monitoring
US9595378Sep 19, 2013Mar 14, 2017Witricity CorporationResonator enclosure
US9596005Jun 21, 2013Mar 14, 2017Witricity CorporationWireless energy transfer using variable size resonators and systems monitoring
US9601261Apr 13, 2010Mar 21, 2017Witricity CorporationWireless energy transfer using repeater resonators
US9601266Oct 25, 2013Mar 21, 2017Witricity CorporationMultiple connected resonators with a single electronic circuit
US9601270Feb 26, 2014Mar 21, 2017Witricity CorporationLow AC resistance conductor designs
US9602168Oct 28, 2014Mar 21, 2017Witricity CorporationCommunication in wireless energy transfer systems
US9634495Nov 24, 2014Apr 25, 2017Duracell U.S. Operations, Inc.Wireless power transfer using separately tunable resonators
US20070222542 *Jul 5, 2006Sep 27, 2007Joannopoulos John DWireless non-radiative energy transfer
US20070285619 *Jun 8, 2007Dec 13, 2007Hiroyuki AokiFundus Observation Device, An Ophthalmologic Image Processing Unit, An Ophthalmologic Image Processing Program, And An Ophthalmologic Image Processing Method
US20080278264 *Mar 26, 2008Nov 13, 2008Aristeidis KaralisWireless energy transfer
US20090195332 *Mar 31, 2009Aug 6, 2009John D JoannopoulosWireless non-radiative energy transfer
US20090195333 *Mar 31, 2009Aug 6, 2009John D JoannopoulosWireless non-radiative energy transfer
US20090267709 *Mar 31, 2009Oct 29, 2009Joannopoulos John DWireless non-radiative energy transfer
US20090267710 *Mar 31, 2009Oct 29, 2009Joannopoulos John DWireless non-radiative energy transfer
US20100164296 *Dec 28, 2009Jul 1, 2010Kurs Andre BWireless energy transfer using variable size resonators and system monitoring
US20110080054 *Oct 6, 2010Apr 7, 2011Tdk CorporationWireless power feeder and wireless power transmission system
US20110193421 *Apr 15, 2011Aug 11, 2011Tdk CorporationWireless power feeder, wireless power receiver, and wireless power transmission system
US20110198940 *Apr 18, 2011Aug 18, 2011Tdk CorporationWireless power feeder, wireless power receiver, and wireless power transmission system
EP2515414A4 *Nov 18, 2009Apr 6, 2016Toshiba KkWireless power transmission device
Classifications
U.S. Classification343/904
International ClassificationH01Q1/00
Cooperative ClassificationY02B60/50, H04B17/318, H04B5/0037, H01Q21/28, H01F38/14, H04B5/00, H04B5/0081, H01Q7/00
European ClassificationH01Q21/28, H01Q7/00, H04B17/00B1R, H04B5/00
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